Breakdown of Kasayı kullanıp kullanmadığını ve bornoz giyip giymediğini merak ediyorum.
ve
and
giymek
to wear / to put on
kullanmak
to use
merak etmek
to wonder, to be curious
Questions & Answers about Kasayı kullanıp kullanmadığını ve bornoz giyip giymediğini merak ediyorum.
How does kullanıp kullanmadığını translate to "whether or not he used"?
This is the structure taught in this lesson for indirect yes/no questions! You take the positive verb root and add -(y)ıp (kullanıp), then follow it with the negative verb root, the participle -dık, and a possessive suffix (kullanmadığı). Literally, it acts like "his using and his not using."
How do we know the sentence is about whether he used the safe, rather than I or you?
The subject of an indirect question is shown by the possessive suffix on the second half of the verb pair. In kullanmadığı, the -ı after the -dık (which mutated to -dığ) is the third-person singular possessive suffix ("his/her"). If it were about you, it would be kullanıp kullanmadığını (with your possessive -ın + accusative -ı), which actually looks identical here but changes based on context!
Why is there an extra -nı and -ni at the very end of kullanmadığını and giymediğini?
Those are accusative case endings. The main verb merak ediyorum (I wonder) needs its direct object to have the accusative case. Since you are wondering about the whole "whether or not" phrase, the entire phrase becomes the object. The -n- is just a buffer letter separating the possessive -ı/-i and the accusative -ı/-i.